# NAG Library Routine Document

## 1Purpose

To supply individual optional parameters to e04ugf/e04uga. More precisely, e04ujf must be used to supply optional parameters to e04ugf and e04uja must be used to supply optional parameters to e04uga.
e04uja is a version of e04ujf that has additional arguments in order to make it safe for use in multithreaded applications (see Section 5). The initialization routine e04wbf must have been called before calling e04uja.

## 2Specification

### 2.1Specification for e04ujf

Fortran Interface
 Subroutine e04ujf ( str)
 Character (*), Intent (In) :: str
#include nagmk26.h
 void e04ujf_ (const char *str, const Charlen length_str)

### 2.2Specification for e04uja

Fortran Interface
 Subroutine e04uja ( str,
 Integer, Intent (Inout) :: iwsav(550) Integer, Intent (Out) :: inform Real (Kind=nag_wp), Intent (Inout) :: rwsav(550) Logical, Intent (Inout) :: lwsav(20) Character (*), Intent (In) :: str
#include nagmk26.h
 void e04uja_ (const char *str, logical lwsav[], Integer iwsav[], double rwsav[], Integer *inform, const Charlen length_str)

## 3Description

e04ujf/e04uja may be used to supply values for optional parameters to e04ugf/e04uga. It is only necessary to call e04ujf/e04uja for those arguments whose values are to be different from their default values. One call to e04ujf/e04uja sets one argument value.
Each optional parameter is defined by a single character string, of up to $72$ characters, consisting of one or more items. The items associated with a given option must be separated by spaces, or equals signs $\left[=\right]$. Alphabetic characters may be upper or lower case. The string
`Print Level = 1`
is an example of a string used to set an optional parameter. For each option the string contains one or more of the following items:
 – a mandatory keyword; – a phrase that qualifies the keyword; – a number that specifies an integer or real value. Such numbers may be up to $40$ contiguous characters in Fortran's I, F, E or D formats, terminated by a space if this is not the last item on the line.
Blank strings and comments are ignored. A comment begins with an asterisk (*) and all subsequent characters in the string are regarded as part of the comment.
For e04ujf, each user-specified option is normally printed as it is defined, on the current advisory message unit (see x04abf), but this printing may be suppressed using the keyword Nolist. Thus the statement
```
Call e04ujf ('Nolist')
```
suppresses printing of this and subsequent options. Printing will automatically be turned on again after a call to e04ugf and may be turned on again at any time using the keyword List.
For e04uja printing is turned off by default, but may be turned on at any time using the keyword List.
Optional parameter settings are preserved following a call to e04ugf/e04uga and so the keyword Defaults is provided to allow you to reset all the optional parameters to their default values before a subsequent call to e04ugf/e04uga.
A complete list of optional parameters, their abbreviations, synonyms and default values is given in Section 12 in e04ugf/e04uga.

None.

## 5Arguments

1:     $\mathbf{str}$ – Character(*)Input
On entry: a single valid option string (as described in Section 3 and in Section 12 in e04ugf/e04uga).
Note: the following are additional arguments for specific use with e04uja. Users of e04ujf therefore need not read the remainder of this description.
2:     $\mathbf{lwsav}\left(20\right)$ – Logical arrayCommunication Array
3:     $\mathbf{iwsav}\left(550\right)$ – Integer arrayCommunication Array
4:     $\mathbf{rwsav}\left(550\right)$ – Real (Kind=nag_wp) arrayCommunication Array
The arrays lwsav, iwsav and rwsav must not be altered between calls to any of the routines e04uja, e04uga, e04uha or e04wbf.
5:     $\mathbf{inform}$ – IntegerOutput
On exit: contains zero if a valid option string has been supplied and a $\text{value}>0$ otherwise (see Section 6).

## 6Error Indicators and Warnings

${\mathbf{inform}}=5$
The supplied option is invalid. Check that the keywords are neither ambiguous nor misspelt.

Not applicable.

## 8Parallelism and Performance

e04ujf/e04uja is not threaded in any implementation.